As Debbie suggested try a reward for going outside. With all of mine I used a tube of Primula cheese and they got a squirt of it when they toileted outside. If its just poo you're having a problem with then maybe just use it as a reward for pooing rather than weeing aswell, it may be more effective that way.
Is he only pooing when you are not there? I was just wondering if it was an anxiety problem? My neighbour had a JRT who poo'd when left on his own, even if he'd just had a poo and even if she only left for 5 minutes.
If he's doing it when you are there too, then I would just think its a toilet training issue. Its funny, because with all of mine the pooing inside stopped almost straight and it was weeing that went on longer. I think all pups are different and I don't think you can set a time limit on how long it takes, some do it quickly some don't.
I find the eating of poo disgusting too. I kind of accept that fox poo, horse poo etc is very exciting to them, but I can't get my head round dog poo.
I have to be quick pick up poo here, particularly Sapphi's, as both the boys think its yummy.